0,1

a(2n)=5*2^n-1 and a(2n+1)=7*2^n-1 or a(n)=(6-(-1)^n)*2^floor(n/2)-1 - Benoit Cloitre (benoit7848c(AT)orange.fr), May 04 2003

A010737 := proc(n) options remember; if n <= 1 then 2*n+4 else 2*A010737(n-2)+1; fi end;

(PARI) a(n)=(6-(-1)^n)*2^floor(n/2)-1

Sequence in context: A085802 A084916 A020747 this_sequence A048625 A120134 A112381

Adjacent sequences: A010734 A010735 A010736 this_sequence A010738 A010739 A010740

nonn,easy

N. J. A. Sloane (njas(AT)research.att.com), Ulrich Hund (hund(AT)math.tu-berlin.de)